To england now where kate middleton, the duchess is spending a second night in the hospital after the announcement she's having a baby but it has been rough so far. Abc's lama hasan with an update on... See More
To england now where kate middleton, the duchess is spending a second night in the hospital after the announcement she's having a baby but it has been rough so far. Abc's lama hasan with an update on her health and the clues you could see in her husband's prince william's face. Reporter: When william arrived at the hospital earlier today, he appeared somber. But after spending more than six hours by his wife's bedside, when the prince emerged -- your hole highness, how is the duchess. Reporter: -- He was clearly more relaxed with a beaming smile. Moments later, the palace gave us a clue to why the change in his expression. "The duchess is continuing to feel better," the statement red, but it went on "but the duchess is remaining in hospital and continues to be treated for hyperemesis gravidarum, the crippling form of morning sickness that causes extreme nausea. Barely 12 weeks along, we're now learning the new details about the weekend when william and kate were forced to go public with the pregnancy. The couple were staying with kate's parents when kate reportedly became so sick, the decision was made to head to the hospital. She didn't need to be taken by an ambulance. It wasn't an emergency dash. Once they had been told by the doctors that they should go to the hospital, they decided that it was fine for william to drive her. And kate walked in, I think she was in quite good spirits despite the fact that she's feeling incredibly nauseous. Reporter: Kate's parents found out their daughter was pregnant over the weekend but the royal couple wanted to keep their baby news a secret until december, to tell the royal family on christmas day. And tonight there are no signs the queen here at buckingham palace or kate's family have gone to see her at the hospital just yet. According to one royal reporter, perhaps it's because they know that prince william is doing such a good job of being by her side, diane.
This transcript has been automatically generated and may not be 100% accurate.